Fourteen years later, a rape victim has stopped sleeping with a knife under her pillow — but the pain is “never ending,” she told a Manhattan judge yesterday.

“It seemed like the whole world had gone black and that the soundtrack to my life was the sound of sirens and screaming,” the victim of monster rapist Lerio Guerrero said in a letter read aloud as the criminal was sentenced to 15 years prison.

In the years after Guerrero held a jagged shard of glass to her neck and dragged her into a Lower East Side alley, her lingering flashbacks and terror cost her sleep, friends and her job, she said.

“My life shrunk,” the woman, who was not in the courtroom, said in the letter, read into the record by prosecutor Martha Bashford, who heads the Manhattan DA’s Sex Crimes Unit.

“I booby-trapped my windows and door, and went to bed with a knife under my pillow; yet I rarely slept,” she wrote.

She has regained some of her former confidence, she wrote, but “I will forever be haunted by that day.”

DA Cyrus Vance Jr. noted that Guerrero could have been apprehended sooner if the new All Crimes DNA Law had been in effect earlier; Guerrero had been busted repeatedly in the past for driving and marijuana offenses, crimes that were not DNA-database eligible until the law was enacted this year.

Guerrero, 33, of Staten Island, pleaded guilty earlier this month to raping, sodomizing and robbing the woman in a 1998 attack only solved when cops — working on a hunch when he was arrested for trespassing near a Brooklyn sex-assault crime scene — collected his DNA off of a discarded cigarette. It matched evidence from the 1998 attack.